Scanning Electron Fractography of Body Centered Cubic (BCC) Metals

Scanning electron fractography is an inherent part of investigations of factors which determine the mechanical properties of materials and their failure. Transition bcc metals show the widest variety of fracture mechanisms under uniaxial tension. Brittle fracture is affected by cleavage from various defects - stress concentrators. In brittle-ductile transition, fracture starts by a tough mode but finishes by a brittle one - by cleavage. A fracture mechanism changes after the tough crack has reached some critical length. Mechanisms of subcritical growth are of cleavage with relaxation, inter-granular fracture and dimpled ones. Dimples are observed in ductile fracture. Cleavage is absent. The dimples are nucleated as a result of both failure of particles and their interfaces and delamination of structure elements. All varieties of observed fracture surface may be described as a result of actions of the following mechanisms - cleavage, cleavage with relaxation, pore coalescence, brittle intergranular or intercellular fracture. Fractographical analysis allows one to obtain information not only about the fracture mechanisms but also such characteristics as: fracture toughness, brittle-ductile transition limits, structure transformations preceding fracture

Kinetics of Twinning and Dislocation Slip During Cyclic Deformation of ZK30 Magnesium Alloy

The present study clarifies the anisotropy of tension-compression behaviour during the cyclic deformation of ZK30 magnesium alloy. Some details of mechanical twinning and dislocation slip are studied by acoustic emission technique and direct video observations. Through the combination of these methods, the overall effect of deformation mechanisms is determined for each loading direction and their effect on the cyclic deformation is highlighted

A Hybrid N-body--Coagulation Code for Planet Formation

We describe a hybrid algorithm to calculate the formation of planets from an initial ensemble of planetesimals. The algorithm uses a coagulation code to treat the growth of planetesimals into oligarchs and explicit N-body calculations to follow the evolution of oligarchs into planets. To validate the N-body portion of the algorithm, we use a battery of tests in planetary dynamics. Several complete calculations of terrestrial planet formation with the hybrid code yield good agreement with previously published calculations. These results demonstrate that the hybrid code provides an accurate treatment of the evolution of planetesimals into planets.Comment: Astronomical Journal, accepted; 33 pages + 11 figure

The effect of excretory-secretory antigen of Trichinella spiralis muscle larvae and antihelmintic mebendazole on melanome ells in vitro and in vivo

Melanom je vrlo agresivna forma tumora kože, koja je u većini sluĉajeva rezistentna na konvencionalnu hemioterapiju. Zbog toga melanom predstavlja veliki izazov za istraživanje novih terapijskih pristupa. Rezultati, dobijeni na animalnim modelima, ukazuju da helminti ili njihovi ekskretorno-sekretorni (ES) produkti mogu da modulišu imuni sistem domaćina, i tako dovedu do smanjivanja intenziteta ili spreĉavanja razvoja autoimunih, alergijskih i malignih bolesti. Sa druge strane, lekovi koji su odobreni za razliĉite indikacije ali ne i za terapiju kancera, a koji poseduju prethodno neprepoznat citotoksiĉni efekat prema malignim ćelijama, mogli bi se brzo naći u primeni i za ovu novu indikaciju. Rezultati dobijeni u in vitro i in vivo uslovima pokazuju da bi jedan od takvih lekova mogao biti mebendazol. Mebendazol je antihelmintik, pripada grupi benzimidazola i široko se koristi u veterinarskoj i humanoj medicini. U ovom radu posebnu pažnju usmerili smo na analizu dejstva ES produkata mišićnih, infektivnih larvi (L1) Trichinella spiralis i mebendazola na melanomske ćelije I) In vitro ispitivanja: a) Ispitivali smo efekat ES L1 antigena i mebendazola na preživljavanje melanomskih ćelija. Humane (Fem-X) i mišje (B16) melanomske ćelije gajene su u jednom sloju i posle 20h tretirane sa po pet rastućih koncentracija ispitivanih supstanci (ES L1 antigen: 12.5–200 μg/ml, i mebendazol: 0.007-2.5μM) u kompletnom hranljivom medijumu. Kontrola se sastojala od ćelija gajenih u samom medijumu. Preživljavanje ćelija je odreĊivano korišćenjem metode redukcije dimetiltiazol difenil tetrazolijum bromida (MTT test) 72 sata nakon dodavanja antigena. Dobijeni rezultati ukazuju da ES L1 sntigen T. spiralis na statistiĉki znaĉajan naĉin ispoljava blago smanjenje preživljavanja kod obe melanomske linije. Mebendazol je, takoĊe, doveo do smanjenja preživljavanja kod melanomskih ćelija. Kod obe ispitivane supstance ustanovljeno je da je jaĉi efekat prema humanim melanomskim ćelijama nego prema mišjim, ali to nije bilo statistiĉki znaĉajno...Melanoma is a very aggressive form of skin cancer. It is in most cases resistant to conventional chemotherapy. Because of that it represents a great challenge for investigation of new therapeutic approaches. It is well known that co infection with different pathogens, including helminths and in particular Trichinella spiralis (T. spiralis), can ameliorate (alter) the progression of different diseases (autoimmune, allergic) including malignant one. Drugs approved for indications other than cancer that possess previously unrecognized cytotoxicity toward malignant cells could be rapidly used for this new indication. Data suggest that one of drugs with such indication could be mebendazole. Benzimidazole anthelmintics including mebendazole are widely used in human and veterinary medicine. We studied the in vivo and in vitro effect of: a) T. spiralis excretory-secretory muscle larvae (ES L1) antigen and b) mebendazole on the melanoma cells. I) In vitro studies: a) We investigated the effect of ES L1 antigen and mebendazole on the survival of melanoma cells. Human melanoma (Fem-x), and mouse melanoma (B16) tumor cells were cultured as a monolayer and after 20h treated with five different concentrations of investigated compounds (ES L1 antigen: 12.5–200 μg/ml, and mebendazole: 0.007-2.5μM) in complete nutrient medium. Control consisted of cell cultivated in medium alone. Cell survival was determined 72 h later by using reduction of 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT test). Obtained results indicated that T. spiralis ES L1 antigen, in a statistically significant manner, exerted a mild survival inhibition of target tumor cell lines. Mebendazole exerted strong inhibition of the survival. With both compounds stronger effect was determined toward human melanoma tumor cells compared with the effect on mouse melanoma cells. b) Also, we investigated the effect of ES L1 antigen (50-200 μg/ml) and mebendazole (1.25-5μM) on the apoptosis of mouse B16 melanoma cells. Apoptosis was measured after cultivation of the cells for 72h with ES L1 antigen, and for 24h with mebendazole..

The structure of Green functions in quantum field theory with a general state

In quantum field theory, the Green function is usually calculated as the expectation value of the time-ordered product of fields over the vacuum. In some cases, especially in degenerate systems, expectation values over general states are required. The corresponding Green functions are essentially more complex than in the vacuum, because they cannot be written in terms of standard Feynman diagrams. Here, a method is proposed to determine the structure of these Green functions and to derive nonperturbative equations for them. The main idea is to transform the cumulants describing correlations into interaction terms.Comment: 13 pages, 6 figure

Supplementary data for article: Vojislavljević-Vasilev, D.; Janjić, G. V.; Ninković, D.; Kapor, A.; Zarić, S. The Influence of Water Molecule Coordination onto the Water-Aromatic Interaction. Strong Interactions of Water Coordinating to a Metal Ion. CrystEngComm 2013, 15 (11), 2099–2105. https://doi.org/10.1039/c2ce25621e

Supplementary material for: [https://doi.org/10.1039/c2ce25621e]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1602